It is known to build a long, permanent ramp for entrance into a building. While negotiating such ramp may be entirely feasible for a person in a motor-driven wheel chair, a large percentage of wheel chair users are without motor drive. For such users, negotiating wheel chair ramps is a physically challenging task which they may not be able to fulfill. Thus, for such a wheel chair user, such inclined ramps are as much a barrier as are the steps.
It is also known to provide permanent installation lift devices which remain in a horizontal orientation when lifting a wheel chair user to the higher level. However, such devices are quite massive, and respectively expensive.
It is known to provide a simple ramp which pivots about the lower elevation, from which access is to be had into the building. However, such ramp requires special construction of both the steps and the underlying support at the lower elevation, and thus such ramp requires a relatively costly installation.
It is an object of this invention to provide an improved wheel chair lift device which is light in weight, simple to construct, and simple to install and use.
It is another object to provide a wheel chair lift device which operates as an inclined ramp for negotiating between upper and lower elevations, and which operates as a powered lift for negotiating from the lower elevation to the higher elevation, as well as from the higher elevation to the lower elevation.
It is yet another object to provide a lift device which provides for the user to advance onto the ramp in a generally horizontal orientation at an entrance element thereof, up to a rising element thereof, and then to activate a lift mechanism to raise the ramp, and thus the rising element thereof, to a more nearly horizontal orientation, for traverse of the rising element of the ramp by the wheel chair user with minimal expenditure of effort.
It is yet another object to provide a lift device having provision for raising and mechanically locking an arrestor plate, to prevent inadvertent egress of the wheel chair off the lower end of the ramp when the lower end of the ramp is lifted off the ground, in the lift mode.
It is still another object to provide such a lift device which is modular, self-contained, and portable from place-to-place, and which thus may be moved from place-to-place for temporary uses, with little if any installation cost or effort.
It is yet a further object to provide a lift device which can be adjusted for accessing a range of heights of steps.